Seminar Presentation on Scene Typhus

1. In a sub centre area of Wayanad district, 5
cases were brought with history of fever,
chills, myalgia and constitutional symptoms.
O/E there is macular rash and a punched-out
ulcer covered with a blackened scab
•What is your probable diagnosis?
•Write the epidemiological determinants
•Write a note on control measures

2. ClinicalPresentation– Eschar
…a pathognomonicsign
• Apainless papule occurs at the bite site, later ulcerates, & transforms into
a black crust or ‘eschar’in a variable proportion of patients, the border of
the eschar is surrounded by reddisherythema.
• Difficult tospot in darker individuals; moist intertriginous surfacesmay be
missed if not looked intocarefully

3. ClinicalPresentation -Eschars

4. Onset:Appears at the end of the 1st week, lasts
3~7days.
Location: Chest, abdomen, whole trunk, or upper
and lower limbs. rarely involves the face, palms
and soles.
 Initially rash is in the form of pink, blanching,
discrete maculae which subsequently becomes
maculopapular, petechial or hemorrhagic.
Maculopapular Rash

5. Lymphadenopathy
 Regionallymphadenopathy:
occursat the end of the 1stweek.
localize:the draining lymph node around theprimary eschar
characterizedby tenderness and enlargement
 Generalizedlymphadenopathy:appears 2-3 days later.

6. Clinical Features

8. SCRUBTYPHUS
• Aka., Japaneseriver fever
• known in Japanese folklore to be associated with the jungle mite
or chigger, termed ‘tsutsugamushi’ inJapanese
• (tsutsuga =disease,harm, noxious and mushi =bug).
• is azoonosis, with humans being accidental,dead
end hosts

9. Incubation Period
• 7–21 days(mean, 10–12 days)

10. ClinicalPresentation- Complications
• More virulent strains of O. tsutsugamushi can cause
Respiratory
• interstitial
pneumonitis
• overwhelming
pneumonia with ARDS
Cardiac
•Toxic myocarditis
Hematological
• Thrombocytopenia
• Pancytopenia
• disseminated
intravascular
coagulation (DIC)
Neuropsychiatric
• Meningitis, Encephalitis
• Cochlear component of 8th nerve
involvement
• Transverse Myelitis
Abdominal
• acute hepatic failure
• acute renal failure
• GI bleeding
• para-aortic, portahepatic and the
splenic hilar lymphadenopathy

11. DDx– “typhus-like illness”
Typhus
(SFG, TG and/or STG)
distinguished only by specific serological tests with
acute and convalescent samples (IFA, IIP, ELISA, RFD) or
PCR assays tests, same treatment for all
Malaria by stained blood films, antigen detection assays
Arbovirus infections
(e.g. dengue, chikungunya)
serological methods (NS1, IgM, IgG assays). Dengue rash
is finer and more erythematous than scrub typhus and
with marked thrombocytopenia
Leptospirosis PCR (full blood) or culture (blood, CSF)
Relapsing fever
(lice or ticks)
demonstration of Borrelia in blood smears, serology or
PCR
Meningococcal disease blood and CSF cultures
Typhoid blood and bone marrow cultures
Viral fevers with macular rash, for example Epstein–Barr virus,
infectious mononucleosis, and primary HIV infection,
distinguished serologically

12. How to diagnose?..
• Diagnosis is greatly hampered by the lack of accurate andaccessible
laboratory diagnosis.
• Given the large populations of India and China, the numbers
potentially exposed areenormous.
• With the growth of ecotourism in Asia, more travellers are returning
to non-endemic areas with thisdisease.

13. LABORATORYDIAGNOSIS
Weil-Felix test
ELISAbased tests, particularly immunoglobulin M (IgM)capture
assays
Molecular diagnosis byPCR
Indirect ImmunoperoxidaseAssay(IPA)
ImmunofluorescenceAssay(IFA)
GOLD STANDARD

14. Supportive laboratoryInvestigations
• ChestX-Rayshowing infiltrates, mostly
bilateral
• WBCcount may become elevated tomore
than 11,000 / cu. mm.
• Thrombocytopenia (i.e. <1,00,000/ cu.mm)is
seenin majority ofpatients.
Before admission
• RaisedTransaminaselevels are commonly
observed
After treatment

17. Agent
Budding of O. tsutsugamushi on the cellular surface
• gram-negative, rod-shaped (cocco-bacillus) bacterium
Orientia (Rickettsia) tsutsugamushi.
• wide phenotypic and genotypicdiversity
• reported serotypes are
Karp, Kato, Gilliam, Boryong, Kawazaki
• does not have a vacuolar membrane and
hence it grows freely in the cytoplasm of
infected cells.
• Cell wall lackslipopolysaccharide and
peptidoglycan and doesnot haveanouter
slime layer

18. Vector - PrimaryReservoir
• Transmitted by bite of infected larvae of the trombiculid mite
Leptotrombidiumdeliense(“chiggers”)
• feeds on lymph and tissue fluid rather than blood.
• bite ofthe mite leaves acharacteristic black eschar

19. Earlier it was thought that
rodents were the natural
reservoir of infection, but it
is now believed that mites
are both the vector and the
reservoir.
Natural Reservoir

21. Grasslands
Areas Around Houses
Rice Fields
The term scrub of scrub
typhus came from the
type of vegetations
(terrain between woods
& clearings) that harbor
the vectors.
Moist Areas: Swamp & Bog
Chigger’s Habitats

22. PREVENTION & CONTROL
MEASURES

23. CONTROLSTRATEGY
Public
Education
Rodent
Control
Habitat
Modification
Case
Identification
&
Treatment

24. Rapid case identification by health-care workers
Public education on case recognition and personal
protection
Rodent control and habitat modification
THREE PILLARS OF PROGRAMME
TO CONTROL SCRUB TYPHUS

25. Early diagnosis and treatment
•Proper history taking
•Clinical examination- look out for eschar in
hidden areas
•Investigations
•Treatment
•Health education
INDIVIDUAL LEVEL

26. TREATMENT
• Without waiting for laboratory confirmation of the Rickettsial
infection, antibiotic therapy should be institutedwhen rickettsial
disease is suspected.
• Antibiotic therapy brings about prompt disappearance of the fever
and dramatic clinical improvement.
• Rapid defervescence after antibiotic treatment is socharacteristicthat
it is used asadiagnostic test for O.tsutsugamushiinfection

27. Primary Health CentreLevel
• Lesssevere cases.....
ADULT CHILDREN PREGNANCY
Doxycycline 200 mg/day in
two divided doses for 7
days
Or
Azithromycin 500 mg in a
single oral dose for 5
days.
Azithromycin 10mg/kg body
weight in a single oral dose
for 5 days.
Azithromycin 500 mg in a
single oral dose for 5
days.
Chloramphenicol is 50-
100 mg/kg/d PO/IV
divided q6h;not to exceed
4 g/d with serum levels
being monitored closely
Or Or
Chloramphenicol 500 mg
PO qid for 7-14 days

28. Primary Health CentreLevel
If presentswith Complications
• Refer to secondary or tertiary centre - ARDS,acute renalfailure,
meningo encephalitis, multi-organ dysfunction.
• Doxycycline should be initiated before referring thepatient.
• In addition to recommended management of community acquired
pneumonia, Doxycycline is to beinitiated when scrub typhus is
considered likely.

29. •Health education regarding scrub typhus, personal
prophylaxis
•Screening for disease
•Early diagnosis and prompt treatment of family
members if detected with disease
•Chemoprophylaxis
FAMILY LEVEL

30. Prophylaxis
• Recommended under special circumstances where disease isendemic.
• Oralchloramphenicol or tetracycline given once every 5 daysfor
thirty-five daysor weekly dosesof doxycycline during and for6 weeks
after exposure have both been shown to be effectiveregimens.
• Resistance to antibiotics hasbeen noted inseveral areas, therefore
prophylaxis with antibiotics cannot beguaranteed.

31. Vaccineagainstscrub typhus?
• There is enormous antigenic variation in Orientia tsutsugamushi
strains, and immunity to one strain does not confer immunity to
another
• Avaccine developed for one locality may not be protective inanother
locality, becauseof antigenicvariation.
• Thiscomplexitycontinuesto hamper efforts to produce aviable
vaccine

32. •Application of all levels of prevention in community
•Research / investigation of condition in detail
•Cooperate with local self government to initiate
projects
•Public awareness through mass media
•Control measures
•Habitat modification
COMMUNITY LEVEL

33. more likely to occur in those living close to bushes
and wood piles, farmers, rodent observers and those
rearing domestic animals
avoid going to such places like farms, areas
abundant of bushes, rodents and domestic animals
Healthy life style education
Personal hygiene
Primordial prevention

34. Health promotion and Specific protection
Health promotion - health education &
environmental modification
•Advocacy, awareness and education activities-
targeted at school children, teachers and women
groups in endemic areas
•Habitat modification -by good sanitation in and
around buildings by clearing vegetation and by use of
natural predators of rats. Rat population can also be
controlled by measures like poisoning and rat
trapping as an environmental measure
Primary prevention

35. VECTOR CONTROL:
•Clearing vegetation where rats and mice live
•Application of insecticides – lindane or chlorane to
ground and vegetation

36. specific protection
PERSONAL PROPHYLAXIS
Wearing protective clothing
Impregnating clothes & blankets with miticidal
chemicals (benzyl benzoate)
Application of mite repellants (diethyltoluamide) to
exposed skin surfaces
Avoiding sitting or lying on bare ground or grass
No vaccine exists at present

37. •Once the disease has occurred-Early diagnosis and
Treatment
•increase awareness of empirical therapy options for
scrub typhus and to develop diagnostic assays that
are affordable, require limited expertise and
equipment, and are sensitive and specific such that
can be used in endemic, resource poor countries
Secondary prevention

38. Takehome message
Scrub typhus is a re-emerging disease in India.
an important cause of community acquired undifferentiated febrile illness in India.
It has to be considered in the differential diagnosis of sepsis and multiorgan dysfunction
syndrome.
Failure of early diagnosis is associated with significant mortality and morbidity and also leads
to expensive PUO workup.
Search for an eschar in hidden areas of body.
Screening by Weil-Felix & Diagnosis is done by IgM scrub typhus ELISA.
Drug of choice - - - - Doxycycline.

39. THANK YOU